Example of keeping a class immutable, meaning that from the outside you are not able to modify the object after it has been instantiated.

example.php

<?php

class User
{
    /**
     * @var int
     */
    private $id;

    /**
     * @var string
     */
    private $name;

    /**
     * @var string
     */
    private $email;

    /**
     * @var null|string
     */
    private $passwordHash = null;

    /**
     * User constructor.
     *
     * @param int    $id
     * @param string $name
     * @param string $email
     * @param string $passwordHash If you already have an user, you want to create a user with the existing hash
     */
    public function __construct(int $id, string $name, string $email, string $passwordHash = null)
    {
        $this->id           = $id;
        $this->name         = $name;
        $this->email        = $email;
        $this->passwordHash = $passwordHash;
    }

    /**
     * @return int
     */
    public function id() : int
    {
        return $this->id;
    }

    /**
     * @return string
     */
    public function name() : string
    {
        return $this->name;
    }

    /**
     * @return string
     */
    public function email() : string
    {
        return $this->email;
    }

    /**
     * Check if a given password matches the users password.
     * 
     * @param string $password
     *
     * @return bool
     */
    public function checkPassword(string $password) : bool
    {
        return password_verify($password, $this->passwordHash);
    }

    /**
     * Get a clone of this instance but with the given name.
     * 
     * @param string $name
     *
     * @return User
     */
    public function withName(string $name) : User
    {
        $clone = clone $this;
        $clone->name = $name;
        
        return $clone;
    }

    /**
     * Get a clone of this instance but with the given email.
     *
     * @param string $email
     *
     * @return User
     */
    public function withEmail(string $email) : User
    {
        $clone = clone $this;
        $clone->email = $email;

        return $clone;
    }

    /**
     * Get a clone of this instance but with the given password.
     *
     * @param string $password
     *
     * @return User
     */
    public function withPassword(string $password) : User
    {
        $clone = clone $this;
        $clone->passwordHash = $this->hashPassword($password);

        return $clone;
    }

    /**
     * A small helper method that handles the password hashing.
     * 
     * @param string $password
     *
     * @return string
     */
    private function hashPassword(string $password) : string
    {
        return password_hash($password, PASSWORD_BCRYPT);
    }
}

///////////////////////////////////////////////////////////////////////////////
// Example
///////////////////////////////////////////////////////////////////////////////

// You can only create a new User if you provide all
// the needed constructor arguments.
$user = new User(
    1,
    'John',
    'john@example.com'
);

// Create a new user with the password set to the given value
$user = $user->withPassword('secret');

// Create a new user with the email changed
$user = $user->withEmail('john.doe@example.com');

// Some output
var_dump($user->checkPassword('wrong')); // false
var_dump($user->checkPassword('secret')); // true
var_dump($user->id()); // 1
var_dump($user->name()); // 'John'
var_dump($user->email()); // 'john.doe@example.com'